This invention comprises a liner for a fireplace grate comprising a single sheet of steel of generally rectangular shape, having a concave cross-section along its length when placed on a grate and facing upwardly. The sheet has a plurality of uniformly spaced apart holes across the length and width thereof. The gauge or thickness of the sheet is sufficient to bear the weight of fuel to be placed thereon and to resist premature destruction from the ravages of use. The size and number of holes in the sheet are sufficient to enable efficient burning of logs and other materials.
The grate of this invention has several advantages in that it is placed on top of a fireplace grate so that the apertures in the sheet function as draft control units to permit the natural flow of air through the sheet to pass over the fuel while retaining the live embers to thereby maximize the heating value of the fuel. In short, the live embers directly under the fuel act as part of a positive thermal enhancer that is activated by a flow of air through the unit. This is in contrast to a conventional fireplace grate wherein the draft of air enters the fire box in an uncontrolled volume and flows over the fire and upward causing a greater portion of thermal energy to exit through the chimney.
The essential feature of this invention is the use of a metal liner, preferably mild steel, for placement on a grate to assist in the burning of fuel. Although the general concept has been proposed heretofore, none of the prior art devices have functioned to provide the efficiency and other advantages of the liner of the present invention. One example of a prior art liner is shown in U.S. Pat. No. 3,536,057 to Grosso. It comprises a generally U-shaped screen of a rectangular configuration supported by a fireplace grate or the like. The screen comprises woven wires which are spaced between about 1/8 to 3/8 of an inch apart. The wire is an iron alloy intended to resist sagging and other damage resulting from exposure to high temperatures. The woven screen is made and shaped in arcuate fashion and of generally rectangular configuration along its length. However, the relatively large openings between wires does not permit the ashes and embers to be properly retained in the fireplace, and the advantages of a controlled flow of air are not realized. Also, the wires do not hold up over a continued period of use that would permit such a device to function over an extended period of time. Frequent replacement is necessary.
Another example in the prior art is U.S. Pat. No. 1,823,576 to Stieqlitz which discloses a perforated flat fuel supporting plate for separating the ash pit section and the fire box section of a conventional furnace. It does not disclose or relate to a fireplace for producing heat.
A still further design is disclosed in U.S. Pat. No. 3,505,986 to Wood of 1970 which shows a steel plate of arcuate shape with specially designed apertures to enable metal rods to be placed in an upstanding position at specified locations on the plate. The rods are placed in the apertures to hold wooden logs which are loaded at selected points on the arcuate plate. Although the rods are intended to hold fuel such as logs in a manner that is intended to provide certain advantages with respect to combustion of logs and the like, the apertures fail to provide the draft of air necessary to promote combustion. Such an arrangement thus fails to recognize the great advantages to be achieved by retaining the embers of the coals or logs on the arcuate flat surface of a fully perforated sheet as in the case of the present invention. In fact it does not disclose a fully perforated sheet, and the type of apertures disclosed are such that they are easily clogged and thus fail to promote the flow of air through the sheet.